Other than FAQ's related directly
to our products, all comments
reflected are simply the opinions of FAC
of America.
The Distance Between the Vehicle and Traffic Signal (applicable to any
system, any manufacturer)
MIRT, 3M Opticom®, and Tomar
Strobecom® traffic signal preemption are
optically-based communications systems. There are three major factors that
determine range in any optical system: the transmitter (power supply and
strobe head located in the vehicle), the detector (also known as the
“receiver” normally located on or near the traffic signal), and the
optical medium between them (air).
In a perfect world, the transmitter is working perfectly and the lens
covering the strobe head is perfectly clean; the detectors sensitivity is
optimally set, the detector’s lens is perfectly clean, and the traffic
signal electronics are functioning correctly; and there is no visible
obstruction between the transmitter and detector, no fog or bad weather.
It is reasonable to expect any working “system” to function properly at a
distance of between 150 feet and 1800 feet, the distance between
vehicle-mounted transmitter and the traffic signal detector.
Transmitter: Dirty lens, electronic failure of the
power supply, faulty strobe head, insufficient power supply input voltage,
and faulty cables and/or wiring harnesses can decrease or prevent a system
from working properly. Removal of the Infrared Filter on the MIRT will
provide much better range.
Detector: Decreased range or system failure can be
caused by a dirty lens, electronic failure of the preemption detector or
traffic signal electronics (damage due to lightning, circuit component
failure, etc.), power outage to the intersections, improper sensitivity
settings, improper aiming of the “telescopes”, improper mounting
locations, or detectors which have been pre-programmed to only permit
vehicles that can transmit encrypted ID optical signals (Note: See “Will
the MIRT work with encoded detectors?” for specific information related to
encrypted ID optical signals)
Medium: The line-of-sight between the transmitter and
detector can be compromised by fog, smog, snow, rain, sleet, hail, dust,
wind (detectors mounted on suspended lines can sway and/or rock in the
wind, interrupting the line-of-sight), or any combination of the
aforementioned. The line-of-sight can also be obstructed by other vehicles
(notably large trucks), large traffic signs, overpasses (normally due to
improper location of the detector, which can often be corrected by either
relocating the detector or adding another detector), or any
non-transparent physical obstruction.
Removal of the Infrared Filter and proper location of the MIRT when
installed inside the vehicle windshield. The Mirt should be installed with
the suction cups high on the windshield to provide a better line of sight.
The MIRT should be mounted to point straight forward and be level.
System range optimization is a balance between the user’s needs and the
preemption equipment’s capabilities. For instance, if the equipment used
claims a line-of-sight operation up to 1800 feet, yet your requirement is
2500 feet, then no optimization on the part of the user will overcome the
product’s limitations.
Physical obstructions that cannot be resolved by relocating the
detector (receiver) or adding another detector can also not be improved
upon. It is assumed that the reader has established that the system is, in
fact, working, although the range has been determined to be substantially
less than stated in the product specifications bulletins.
Assuming an unobstructed line-of-sight between the transmitter and
detector of 1800 feet, clean transmitter and detectors lenses, and that
both electronic systems are fully operational, suggestions for improving
the range of any intersection are as follows:
- Make certain that the detector is mounted and aimed properly (refer
to the manufacturer’s product manuals).
- Make certain that the MIRT is properly mounted on the vehicle and is
not optically occluded (obstructed or partially blocked), and relocate
if necessary.
- Increase the sensitivity of the detector (refer to the
manufacturer’s product manuals).
If, after all else fails:
The detector (receiver) lens should also be cleaned on a regular basis.
Road dust and dirt (or worse!) can and will collect on the lens of even
the best-designed product. Traffic signal detectors should be tested
frequently, particularly during the warm weather months when thunderstorms
are more common (nearby ground strikes can and will damage even the best
protected electrical apparatus)
Safety Alert! NEVER “assume” that a preemption-equipped traffic signal
is operating properly! The Confirmation Light (high intensity flood lamp
that is often located near the detector on the traffic signal to alert the
emergency vehicle driver that he has gained control of the intersection)
may not be illuminating because the detector isn’t working!!! ALWAYS
PROCEED WITH CAUTION!!! NEVER “ASSUME” THAT THE CONFIRMATION LIGHT IS
BURNT OUT!!!
The short answer is “yes”, for maximum range remove the enternal IR
filter.
Legal Alert! Some states restrict the use of
specifically colored warning lights, including strobes, for specific
purposes only. Please click here to go a chart for each state's Department
of Transportation website link
Yes. The MIRT product are compatible with 3M Opticom® and Tomar®
traffic signal preemption detectors.
Preemption-equipped traffic signals that are programmed to only respond
to custom-encoded preemption transmitters will not work with any MIRT
product at this time. However, the actual percentage of
preemption-equipped intersections that only respond to custom-encoded
transmitters is very small.
Yes. FAC of America does not offer transmitter ID encryption of its
devices at this time due to the logistical problems and liability often
created where such systems are deployed. If a preemption-equipped traffic
signal is programmed so that it permits access only to predetermined
vehicles, every single traffic signal within the territorial boundary of
the equipped emergency vehicle must be similarly equipped.
The programming of traffic signal preemption detector electronics is
almost never performed by the departments who must make use of them,
making the logistics of maintaining such a system cumbersome, impractical,
and very expensive - particularly when new vehicles are equipped with
transmitters and every traffic signal must then be programmed to accept
the new vehicles - logistical responsibilities that responding departments
cannot directly control.
Liabilities arise when bordering departments, which may have vehicles
equipped with preemption transmitters, cannot gain access to encrypted
intersections or, worse, when it is “assumed” that access can be gained,
creating a potentially high risk situation because the responding
emergency vehicle driver believes that he/she has control and right-of-way
through the intersection.
No. Legal precedents have actually been established that prevent
marketplace competitors from even threatening to void warranties when
competing or interactive devices can not be proven to “harm” the product
under warranty.
“Low Priority” is generally used by mass transit authorities to
increase the time duration of green lights or and/or decrease the time
duration of cross-traffic red lights. “High Priority” takes precedence
over “Low Priority”, and the purpose is to secure control of the
intersection by maintaining a single direction of traffic flow by holding
the traffic signal green until the emergency vehicle has passed through
that intersection. “Low Priority” is generally considered to be 10 hertz
(10 flashes-per-second) while “High Priority” is 14 hertz. The MIRT is
only available in “HIGH PRIORITY” 14 hertz.
FAC of America will not sell traffic control products to individuals
that are not legally authorized to use the devices. However, we provide a
“no obligation authorized distributor agreement”, that will qualify you to
inventory and sell the MIRT to Authorized users, as determined by County,
State and Federal laws.
The “Restricted Sale” agreement is a tool used by FAC of America to
determine the authenticity of the buyer, and to prevent unauthorized
individuals from illegally obtaining the product. We highly recommend that
you take advantage of the huge opportunity to sell this cutting edge
technology, that is the perfect answers for departments with limited
budgets and so many more authorized users.
Legal Alert! Laws vary from state to state. Please
follow the link to each state's Department of Transportation website link
(DOT links).
The “Confirmation Light” is primarily used to “confirm” that the
intersection has been accessed by an approaching emergency vehicle.
Individual state Departments of Transportation determine when the light
actually illuminates, and if it flashes or not.
In most instances, the Confirmation Light will remain illuminated (or
flash) until it no longer detects the preemption transmitter, which is
usually because the emergency vehicle has passed through the
intersection.
You can flash your high beams real fast - it just won’t activate modern
optically-based preemption detectors!
3M Opticom® detectors (receivers) have
advanced circuitry features which are only looking for the very brief
flash of a strobe light, with a precisely timed interval between flashes.
Headlamp high beams (any headlamps) turn off and on very slowly compared
to strobe lights, and controlling the timing of a mechanical switch to
precisely set the interval between flashes might be a fun way to exercise,
but it is a waste of time if the objective is to activate preemption
detectors.
Opticom® is a registered trademark of 3M
Corporation, St. Paul, MN
Strobecom® is a registered trademark of Tomar
Electronics, Inc., Gilbert, AZ
